Set POOL_SIZE to 100 or so in your db settings and tweak this number so that each worker process has adequate postgres connections available to it. If you have four worker processes and max_connections for postgres is 101, then 25 is a reasonable pool size that will still let you run manage commands like south. Each connection to postgres will fork a postgres worker, visible running pstree -pa on Linux systems. Raising max_connections in postgres can consume a lot of memory if work_mem is set high. Work_mem is necessary to do in-memory sorts before spilling to the disk, so don't set this too low just to have tons of postgres threads running.